A Unicode (UCS-2 encoded) file beginning with the Byte Order Mark (BOM, Lisp character
#\U+FEFF
, also known as Zero-Width-No-Break-Space) can now be read by the Lisp reader. The standard lisp readtable now treats this character as whitespace.
This character is written at the start of a UCS-2 encoded file by some programs including Microsoft Notepad and the LispWorks editor. This change allows
read
to work on such files without specially ignoring the BOM.